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The males do not have to compete with other males, and female anemone fish are typically larger. When a female dies a juvenile (male) anemone fish moves in, and "the resident male then turns into a female and reproductive advantages of the large female–small male combination continue". [22] In other fishes sex changes are reversible.
A gonad, sex gland, or reproductive gland [1] is a mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. [2] The male gonad, the testicle, produces sperm in the form of spermatozoa. The female gonad, the ovary, produces egg cells
Fish reproductive organs include testicles and ovaries. In most species, gonads are paired organs of similar size, which can be partially or totally fused. [ 52 ] There may also be a range of secondary organs that increase reproductive fitness .
However, the disease can also develop without the fish showing any external signs of illness, the fish maintain a normal appetite, and then they suddenly die. The disease can progress slowly throughout an infected farm and, in the worst cases, death rates may approach 100 per cent. It is also a threat to the dwindling stocks of wild salmon.
This dual system allowed for more complex sexual dimorphisms and greater adaptability to environmental pressures, such as mate competition and reproductive success. The divergence of hormonal regulation in mammals (testosterone and estrogen dominance) and birds ( estradiol -driven mechanisms) reflects evolutionary fine-tuning built upon the ...
Signals triggered by binding to the receptor are relayed within the cells by the cyclic AMP second messenger system. Gonadotropins are released under the control of gonadotropin-releasing hormone (GnRH) from the arcuate nucleus and preoptic area of the hypothalamus. The gonads — testes and ovaries — are the primary target organs for LH and ...
The human female reproductive system is a series of organs primarily located inside of the body and around the pelvic region of a female that contribute towards the reproductive process. The human female reproductive system contains three main parts: the vulva , which leads to the vagina, the vaginal opening, to the uterus; the uterus , which ...
Birds have only one functional ovary (the left), while the other remains vestigial. In mammals including humans, the female ovary is homologous to the male testicle, in that they are both gonads and endocrine glands. Ovaries of some kind are found in the female reproductive system of many invertebrates that employ sexual reproduction. However ...